We have had a long-standing interest in the etiology of severe insulin resistance. Initially, we identified mutations in the insulin receptor gene and studied a group of patients with autoantibodies against the insulin receptor. More recently, we have concentrated on lipodystrophy syndromes: a group of heterogeneous syndromes characterized by lack of adipose tissue and severe insulin resistance. In collaborations with Dr. Abhimanyhu Garg (University of Texas Southwestern), and Dr. David Savage in the UK, we have reported mutations in the multiple genes in patients with congenital generalized lipodystrophy, familial partial lipodystrophy, and progeroid lipodystrophies. In following patients with lipodystrophy, we have observed that they have a high incidence of proteinuric renal disease. Further, it turns out that the renal abnormality is not diabetic as expected, but most often focal segmental glomerulonephritis or membranoproliferative glomerulonephritis. We are continuing this study in collaboration with Dr. James Balow in an attempt to understand the relationships of these secondary forms of renal disease to lipodystrophy. Another recent observation is that both patients with mutations in their insulin receptors and autoantibodies to the receptor have markedly elevated adiponectin levels in contrast to the low levels that would be expected in this form of extreme insulin resistance. Thus, our longstanding and continued follow-up of patients with syndromic forms of insulin resistance continues to yield new and important information. We have described a new and very effective treatment for the syndrome of autoantibodies to the insulin receptor; an update with greatly increased sample size is anticipated shortly. In addition, we continue to work with collaborators to report novel genetic mutations leading to insulin resistance and lipodystrophy.